Process for obtaining secondary



Patented Jan. 23, 1934 PROCESS FOR OBTAENING SECONDARY ALCOHOLS FROM ACID LIQUORS Benjamin T. Brooks, Greenwich, Conn., assignor, by mesne assignments, to Standard Alcohol Company, Wilmington, DeL, a corporation of Delaware No Drawing. Application May 3, 1932 Serial No. 609,037

13 Claims.

The invention will be fully understood from the following description:

The secondary alcohols of from 3 to 6 carbon atoms to the molecule are produced commercially by the sulphation of olefines followed by the hydrolysis of the alkyl sulphates so produced and the separation of the alcohol by distillation. The olefine material may be obtained by the destructive distillation of a variety of hydrocarbon substances, but the preferred source is the light fraction of the material formed by cracking petroleum oil. A preferred method of generating the olefine material is vapor phase cracking of petroleum oil carried out at a temperature between 1050 and 1150 F. The sulphation is preferably carried out by the application of aqueous sulphuric acid to a close out oleiine fraction containing preferably the normal olefines of a single number of carbon atoms to the molecule, as for example a propylene, butylene or amylene fraction separated by rectification from the products of cracking, thereby forming the alkyl sulphates corresponding to the normal olefines present in the fraction.

Alternatively, however, sulphation reaction may be carried out by the application of aqueous sulphuric acid to a broader fraction containing 2 or more different normal olefines together with such other hydrocarbons as are normally present in a fraction separated by rectification from cracked petroleum. The sulphation treatment may be carried out by contacting sulphuric acid with the olefine material in gaseous condition, as

for example by running them counter-currently through a tower containing the plates or packing necessary to permit intimate contact between gas and vapor, in which case the acid liquor is withdrawn fromthe lower part of the tower. Alternatively, the sulphation may be carried out by contacting a liquid fraction with aqueous sulphuric acid in a suitable agitator. When made by any of the processes mentioned, however, the acid liquor contains considerable hydrocarbon material, principally polymerized hydrocarbons formed during the reaction. The polymers tend to separate on standing but the separation is incomplete, and holding the acid liquor for several hours in concentrated condition results in a decrease in alcohol yield owing to the continuous formation of polymers. This is particularly the case where the acid liquor contains the alkyl sulphates corresponding to butyl, amyl and heXyl alcohols. The preferred procedure is, therefore, to dilute the acid liquor with water as soon as practicable, thereby arresting the polymerization.

The diluted acid liquor may be distilled for the separation of the alcohol content, but in this case some of the hydrocarbon polymer ordinarily distills over with the alcohol and contaminates the same. The presence of even a few percent of hyno drocarbon in the alcohol is highly objectionable, and the removal of the hydrocarbon material may entail considerable difiiculty.

In accordance with my process, the diluted acid liquor is settled, whereupon the hydrocarbon material separates and stratifies as an oil layer above the. aqueous layer containing secondary alcohol and sulphuric acid. The hydrocarbon layer is then carefully separated from the aqueous layer, and the aqueous layer is separately distilled for the recovery of its alcohol content. The hydrocarbon layer contains considerable secondary alcohols, and it is therefore necessary to separately treat the hydrocarbon layer for the recovery of its alcohol content. If it is attempted to separate the alcohol by washing this material with water, emulsification takes place to'such an extent that a clean separation is practically impossible. I

In accordance with my process, the alcohol is separated from the hydrocarbon polymer by the following procedure. The separated hydrocarbon layer is partially distilled, the distillation being carried to the point at which substantially all of the alcohol has been taken overhead, leaving a residue of hydrocarbon polymer in the still of higher boiling point than the separated alcohol. Some of the polymer material passes overhead with the alcohol, and on condensing the overhead is found in solution in the alcohol. However, since the distillate so obtained is entirely free from alkyl sulphates or other emulsifying agents, it is entirely feasible to economically separate the alcohol and any associated hydrocarbon material by Washing with water, and when this condensate is washed, no serious emulsification takes place. I find it to be a further improvement to distil the hydrocarbon layer above referred to with steam. In many cases there appear to be certain compounds in the polymer layer which in contact with the steam react to generate alcohol, thereby increasing the total alcohol yield. This step is preferably carlead or other acid resistant material, or preferably a vitreous material such as stoneware or glass.

Regardless whether the distillation of the polymer layer is carried out with steam or not, the amount of water to be employed in order to separate the alcohol from any associated hydrocarbons will vary in accordance with the natural water solubility of the alcohol present. Thus, in the case of isopropyl alcohol, 1 or 2 volumes of water is sufiicient to effect a good separation. With secondary butyl alcohol, 2 to 4 volumes of water should be added, and in the case of amyl and hexyl alcohol, 5 to 8 volumes of water have been found preferable. After thoroughly mixing the condensate with the water, it is allowed to settle; whereupon the hydrocarbon present in the alcohol separates and stratifies forming the upper layer. The lower aqueous layer is drawn off and the alcohol recovered by any suitable means, preferably by distillation (rectification), through a suitable column.

The foregoing description is for purposes of illustration and not of limitation, and it is therefore my intention that the invention be limited only by the appended claims or their equivalents, in which I have'endeavored to claim broadly all inherent novelty.

I claim:

1. Process of obtaining secondary alcohols of from 3 to 6 carbon atoms to the molecule from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons, separating .said hydrocarbon layer from said aqueous layer, directly and separately partially distilling said hydrocarbon layer, thereby producing a condensate consisting principally of secondary alcohol with minor proportions of hydrocarbon material, and separating the secondary alcohol contained in said condensate from the associated hydrocarbon material.

2. Process of obtaining secondary alcohols of from 3 to 6 carbon atoms to the molecule from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons, separating said hydrocarbon layer from said aqueous layer, directly and separately partially distilling said hydrocarbon layer, thereby producing a condensate consisting principally of secondary alcohol with minor proportions of hydrocarbon material, and separating the secondary alcohol contained in said condensate from the associated hydrocarbon material by washing said condensate with an aqueous liquid.

3. Process of obtaining secondary alcohols of from 3 to 6 carbon atoms to the molecule from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons, separating said hydrocarbon layer from said aqueous layer, directly and separately partially distilling said hydrocarbon layer, thereby producing a condensate consisting principally of secondary alcohol with minor proportions of hydrocarbon material, and separating the secondary alcohol contained in said condensate from the associated hydrocarbon material by washing said condensate with water.

4. Process of obtaining secondary alcohols from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons, separating said hydrocarbon layer from said aqueous layer, directly and separately partially distilling the said hydrocarbon layer while contacting the same with steam, thereby producing a condensate consisting principally of secondary alcohol with minor proportions of hydrocarbon, and separating the secondary alcohol in said condensate from the said hydrocarbon.

5, Process of obtaining secondary alcohols from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons, separating said hydrocarbon layer from said aqueous layer, directly and separately partially distilling the said hydrocarbon layer while contacting the same with steam, thereby producing a condensate consisting principally of secondary alcohol with minor proportions of hydrocarbon, and separating the secondary alcohol in said condensate from the said hydrocarbon by washing said condensate with an aqueous liquid.

6. Process of obtaining secondary alcohols from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons, separating said hydrocarbon layer from said aqueous layer, directly and separately partially distilling the said hydrocarbon layer while contacting the same with steam, thereby producing a condensate consisting principally of secondary alcohol with minor proportions of hydrocarbon, and separating the secondary alcohol in said condensate from the said hydrocarbon by washing said condensate with water.

'7. Process of obtaining secondary alcohols from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons, separating said hydrocarbon layer from said aqueous layer, directly and separately partially distilling the said hydrocarbon layer while passing the same in counter-current contact with steam, thereby producing a condensate consisting principally of secondary alcohol with minor proportions of hydrocarbon, and separating the secondary alcohol in said condensate from the said hydrocarbon.

8. Process of obtaining secondary alcohols from acid reaction products formed by treating olefines with aqueous sulphuric acid, which comprises diluting an acid reaction product with Water, permitting the diluted reaction product to stratify, thereby forming an aqueous layer and a layer consisting predominantly of hydrocarbons,

to stratify, thereby forming an aqueous layer and.

a layer consisting predominantly of hydrocarbons, separating said hydrocarbon layer from said aqueous layer, directly and separately partially distilling the said hydrocarbon layer while passing the same in counter-current contact with steam, thereby producing a condensate consisting principally of secondary alcohol with minor proportions of hydrocarbon, and separating the secondary alcohol in said condensate from the said hydrocarbon by washing said condensate with water.

10. Process of obtaining alcohols from the polymer oil obtained by treating olefines with sulfuric acid, comprising separating the polymer oil from the remainder of the acid reaction mixture, directly distilling the polymer oil without the addition of sulfuric acid to obtain a distillate composed mainly of alcohols, and separating the alcohols from the distillate.

11. Method according to claim 10 in which the alcohols are separated by washing with an aqueous liquid.

12. Process of obtaining alcohols from the polymer oil obtained by treating olefines with sulfuric acid, comprising separating the polymer oil from the remainder of the acid reaction mixture, partially distilling the polymer oil without previously hydrolyzing the same, collecting the distillate composed mainly of secondary alcohols and separating the alcohols from the distillate.

13. Process of obtaining alcohols from the' polymer oil obtained by treating olefines with sulfuric acid, comprising separating the polymer oil from the remainder of the acid reaction mixture, directly treating the polymer oil with steam, collecting the distillate composed mainly of secondary alcohols, and separating the alcohols from the distillate.

BENJAMIN T. BROOKS. 

